Configuration Example: Inter-VLAN Communication
Figure 3-1 illustrates the network topology for the configuration that follows, which shows how to configure inter-VLAN communication using commands covered in this chapter. Some commands used in this configuration are from other chapters.
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Figure 3-1 Network Topology for Inter-VLAN Communication Configuration
ISP Router
Router> enable |
Moves to privileged EXEC mode |
Router># configure terminal |
Moves to global configuration mode |
Router(config)# hostname ISP |
Sets the host name |
ISP(config)# interface loopback 0 |
Moves to interface configuration mode |
ISP(config-if)# description simulated address representing remote website |
Sets the locally significant interface description |
ISP(config-if)# ip address 198.133.219.1 255.255.255.0 |
Assigns an IP address and netmask |
ISP(config-if)# interface serial 0/0/0 |
Moves to interface configuration mode |
ISP(config-if)# description WAN link to the Corporate Router |
Sets the locally significant interface description |
ISP(config-if)# ip address 192.31.7.5 255.255.255.252 |
Assigns an IP address and netmask |
ISP(config-if)# clock rate 4000000 |
Assigns a clock rate to the interface; DCE cable is plugged into this interface |
ISP(config-if)# no shutdown |
Enables the interface |
ISP(config-if)# exit |
Returns to global configuration mode |
ISP(config-if)# router eigrp 10 |
Creates Enhanced Interior Gateway Routing Protocol (EIGRP) routing process 10 |
ISP(config-router)# network 198.133.219.0 0.0.0.255 |
Advertises directly connected networks |
ISP(config-router)# network 192.31.7.0 0.0.0.255 |
Advertises directly connected networks |
ISP(config-router)# end |
Returns to privileged EXEC mode |
ISP# copy running-config startup-config |
Saves the configuration to NVRAM |
CORP Router
Router> enable |
Moves to privileged EXEC mode |
Router># configure terminal |
Moves to global configuration mode |
Router(config)# hostname CORP |
Sets the host name |
CORP(config)# no ip domain-lookup |
Turns off Domain Name System (DNS) resolution to avoid wait time due to DNS lookup of spelling errors |
CORP(config)# interface serial 0/0/0 |
Moves to interface configuration mode |
CORP(config-if)# description link to ISP |
Sets the locally significant interface description |
CORP(config-if)# ip address 192.31.7.6 255.255.255.252 |
Assigns an IP address and netmask |
CORP(config-if)# no shutdown |
Enables the interface |
CORP(config)# interface fastethernet 0/1 |
Moves to interface configuration mode |
CORP(config-if)# description link to L3Switch1 |
Sets the locally significant interface description |
CORP(config-if)# ip address 172.31.1.5 255.255.255.252 |
Assigns an IP address and netmask |
CORP(config-if)# no shutdown |
Enables the interface |
CORP(config-if)# exit |
Returns to global configuration mode |
CORP(config)# interface fastethernet 0/0 |
Enters interface configuration mode |
CORP(config-if)# no shutdown |
Enables the interface |
CORP(config-if)# interface fastethernet 0/0.1 |
Creates a virtual subinterface and moves to subinterface configuration mode |
CORP(config-subif)# description Management VLAN 1 - Native VLAN |
Sets the locally significant interface description |
CORP(config-subif)# encapsulation dot1q 1 native |
Assigns VLAN 1 to this subinterface. VLAN 1 is the native VLAN. This subinterface uses the 802.1q protocol |
CORP(config-subif)# ip address 192.168.1.1 255.255.255.0 |
Assigns an IP address and netmask |
CORP(config-subif)# interface fastethernet 0/0.10 |
Creates a virtual subinterface and moves to subinterface configuration mode |
CORP(config-subif)# description Sales VLAN 10 |
Sets the locally significant interface description |
CORP(config-subif)# encapsulation dot1q 10 |
Assigns VLAN 10 to this subinterface. This subinterface uses the 802.1q protocol |
CORP(config-subif)# ip address 192.168.10.1 255.255.255.0 |
Assigns an IP address and netmask |
CORP(config-subif)# interface fastethernet 0/0.20 |
Creates a virtual subinterface and moves to subinterface configuration mode |
CORP(config-subif)# description Engineering VLAN 20 |
Sets the locally significant interface description |
CORP(config-subif)# encapsulation dot1q 20 |
Assigns VLAN 20 to this subinterface. This subinterface uses the 802.1q protocol |
CORP(config-subif)# ip address 192.168.20.1 255.255.255.0 |
Assigns an IP address and netmask |
CORP(config-subif)# interface fastethernet 0/0.30 |
Creates a virtual subinterface and moves to subinterface configuration mode |
CORP(config-subif)# description Marketing VLAN 30 |
Sets the locally significant interface description |
CORP(config-subif)# encapsulation dot1q 30 |
Assigns VLAN 30 to this subinterface. This subinterface uses the 802.1q protocol |
CORP(config-subif)# ip add 192.168.30.1 255.255.255.0 |
Assigns an IP address and netmask |
CORP(config-subif)# exit |
Returns to global configuration mode |
CORP(config)# router eigrp 10 |
Creates EIGRP routing process 10 and moves to router configuration mode |
CORP(config-router)# network 192.168.1.0 0.0.0.255 |
Advertises the 192.168.1.0 network |
CORP(config-router)# network 192.168.10.0 0.0.0.255 |
Advertises the 192.168.10.0 network |
CORP(config-router)# network 192.168.20.0 0.0.0.255 |
Advertises the 192.168.20.0 network |
CORP(config-router)# network 192.168.30.0 0.0.0.255 |
Advertises the 192.168.30.0 network |
CORP(config-router)# network 172.31.0.0 0.0.255.255 |
Advertises the 172.31.0.0 network |
CORP(config-router)# network 192.31.7.0 0.0.0.3 |
Advertises the 192.31.7.0 network |
CORP(config-router)# end |
Returns to privileged EXEC mode |
CORP# copy running-config startup-config |
Saves the configuration in NVRAM |
L2Switch2 (Catalyst 2960)
Switch> enable |
Moves to privileged EXEC mode |
Switch# configure terminal |
Moves to global configuration mode |
Switch(config)# hostname L2Switch2 |
Sets the host name |
L2Switch2(config)# no ip domain-lookup |
Turns off DNS resolution |
L2Switch2(config)# vlan 10 |
Creates VLAN 10 and enters VLAN configuration mode |
L2Switch2(config-vlan)# name Sales |
Assigns a name to the VLAN |
L2Switch2(config-vlan)# exit |
Returns to global configuration mode |
L2Switch2(config)# vlan 20 |
Creates VLAN 20 and enters VLAN configuration mode |
L2Switch2(config-vlan)# name Engineering |
Assigns a name to the VLAN |
L2Switch2(config-vlan)# vlan 30 |
Creates VLAN 30 and enters VLAN configuration mode. Note that you do not have to exit back to global configuration mode to execute this command |
L2Switch2(config-vlan)# name Marketing |
Assigns a name to the VLAN |
L2Switch2(config-vlan)# exit |
Returns to global configuration mode |
L2Switch2(config)# interface range fastethernet 0/2 - 4 |
Enters interface range configuration mode and allows you to set the same configuration parameters on multiple ports at the same time |
L2Switch2(config-if-range)# switchport mode access |
Sets ports 2–4 as access ports |
L2Switch2(config-if-range)# switchport access vlan 10 |
Assigns ports 2–4 to VLAN 10 |
L2Switch2(config-if-range)# interface range fastethernet 0/5 - 8 |
Enters interface range configuration mode and allows you to set the same configuration parameters on multiple ports at the same time |
L2Switch2(config-if-range)# switchport mode access |
Sets ports 5–8 as access ports |
L2Switch2(config-if-range)# switchport access vlan 20 |
Assigns ports 5–8 to VLAN 20 |
L2Switch2(config-if-range)# interface range fastethernet 0/9 - 12 |
Enters interface range configuration mode and allows you to set the same configuration parameters on multiple ports at the same time |
L2Switch2(config-if-range)# switchport mode access |
Sets ports 9–12 as access ports |
L2Switch2(config-if-range)# switchport access vlan 30 |
Assigns ports 9–12 to VLAN 30 |
L2Switch2(config-if-range)# exit |
Returns to global configuration mode |
L2Switch2(config)# interface fastethernet 0/1 |
Moves to interface configuration mode |
L2Switch2(config)# description Trunk Link to CORP Router |
Sets the locally significant interface description |
L2Switch2(config-if)# switchport mode trunk |
Puts the interface into trunking mode and negotiates to convert the link into a trunk link |
L2Switch2(config-if)# exit |
Returns to global configuration mode |
L2Switch2(config)# interface vlan 1 |
Creates a virtual interface for VLAN 1 and enters interface configuration mode |
L2Switch2(config-if)# ip address 192.168.1.2 255.255.255.0 |
Assigns an IP address and netmask |
L2Switch2(config-if)# no shutdown |
Enables the interface |
L2Switch2(config-if)# exit |
Returns to global configuration mode |
L2Switch2(config)# ip default-gateway 192.168.1.1 |
Assigns a default gateway address |
L2Switch2(config)# exit |
Returns to privileged EXEC mode |
L2Switch2# copy running-config startup-config |
Saves the configuration in NVRAM |
L3Switch1 (Catalyst 3650)
Switch> enable |
Moves to privileged EXEC mode |
Switch# configure terminal |
Moves to global configuration mode |
Switch(config)# hostname L3Switch1 |
Sets the host name |
L3Switch1(config)# no ip domain-lookup |
Turns off DNS queries so that spelling mistakes do not slow you down |
L3Switch1(config)# vtp mode server |
Changes the switch to VTP server mode |
L3Switch1(config)# vtp domain testdomain |
Configures the VTP domain name to testdomain |
L3Switch1(config)# vlan 10 |
Creates VLAN 10 and enters VLAN configuration mode |
L3Switch1(config-vlan)# name Accounting |
Assigns a name to the VLAN |
L3Switch1(config-vlan)# exit |
Returns to global configuration mode |
L3Switch1(config)# vlan 20 |
Creates VLAN 20 and enters VLAN configuration mode |
L3Switch1(config-vlan)# name Marketing |
Assigns a name to the VLAN |
L3Switch1(config-vlan)# exit |
Returns to global configuration mode |
L3Switch1(config)# interface gigabitethernet 1/0/1 |
Moves to interface configuration mode |
L3Switch1(config-if)# switchport trunk encapsulation dot1q |
Specifies 802.1Q tagging on the trunk link (only necessary on older model switches like the 3560 and 3750) |
L3Switch1(config-if)# switchport mode trunk |
Puts the interface into trunking mode and negotiates to convert the link into a trunk link |
L3Switch1(config-if)# exit |
Returns to global configuration mode |
L3Switch1(config)# ip routing |
Enables IP routing on this device |
L3Switch1(config)# interface vlan 1 |
Creates a virtual interface for VLAN 1 and enters interface configuration mode |
L3Switch1(config-if)# ip address 172.16.1.1 255.255.255.0 |
Assigns an IP address and netmask |
L3Switch1(config-if)# no shutdown |
Enables the interface |
L3Switch1(config-if)# interface vlan 10 |
Creates a virtual interface for VLAN 10 and enters interface configuration mode |
L3Switch1(config-if)# ip address 172.16.10.1 255.255.255.0 |
Assigns an IP address and mask |
L3Switch1(config-if)# no shutdown |
Enables the interface |
L3Switch1(config-if)# interface vlan 20 |
Creates a virtual interface for VLAN 20 and enters interface configuration mode |
L3Switch1(config-if)# ip address 172.16.20.1 255.255.255.0 |
Assigns an IP address and mask |
L3Switch1(config-if)# no shutdown |
Enables the interface |
L3Switch1(config-if)# exit |
Returns to global configuration mode |
L3Switch1(config)# interface gigabitethernet 1/0/24 |
Enters interface configuration mode |
L3Switch1(config-if)# no switchport |
Creates a Layer 3 port on the switch |
L3Switch1(config-if)# ip address 172.31.1.6 255.255.255.252 |
Assigns an IP address and netmask |
L3Switch1(config-if)# exit |
Returns to global configuration mode |
L3Switch1(config)# router eigrp 10 |
Creates EIGRP routing process 10 and moves to router configuration mode |
L3Switch1(config-router)# network 172.16.0.0 0.0.255.255 |
Advertises the 172.16.0.0 network |
L3Switch1(config-router)# network 172.31.0.0 0.0.255.255 |
Advertises the 172.31.0.0 network |
L3Switch1(config-router)# end |
Applies changes and returns to privileged EXEC mode |
L3Switch1# copy running-config startup-config |
Saves configuration in NVRAM |
L2Switch1 (Catalyst 2960)
Switch> enable |
Moves to privileged EXEC mode |
Switch# configure terminal |
Moves to global configuration mode |
Switch(config)# hostname L2Switch1 |
Sets the host name |
L2Switch1(config)# no ip domain-lookup |
Turns off DNS queries so that spelling mistakes do not slow you down |
L2Switch1(config)# vtp domain testdomain |
Configures the VTP domain name to testdomain |
L2Switch1(config)# vtp mode client |
Changes the switch to VTP client mode |
L2Switch1(config)# interface range fastethernet 0/1 - 4 |
Enters interface range configuration mode and allows you to set the same configuration parameters on multiple ports at the same time |
L2Switch1(config-if-range)# switchport mode access |
Sets ports 1–4 as access ports |
L2Switch1(config-if-range)# switchport access vlan 10 |
Assigns ports 1–4 to VLAN 10 |
L2Switch1(config-if-range)# interface range fastethernet 0/5 - 8 |
Enters interface range configuration mode and allows you to set the same configuration parameters on multiple ports at the same time |
L2Switch1(config-if-range)# switchport mode access |
Sets ports 5–8 as access ports |
L2Switch1(config-if-range)# switchport access vlan 20 |
Assigns ports 5–8 to VLAN 20 |
L2Switch1(config-if-range)# exit |
Returns to global configuration mode |
L2Switch1(config)# interface gigabitethernet 0/1 |
Moves to interface configuration mode |
L2Switch1(config-if)# switchport mode trunk |
Puts the interface into trunking mode and negotiates to convert the link into a trunk link |
L2Switch1(config-if)# exit |
Returns to global configuration mode |
L2Switch1(config)# interface vlan 1 |
Creates a virtual interface for VLAN 1 and enters interface configuration mode |
L2Switch1(config-if)# ip address 172.16.1.2 255.255.255.0 |
Assigns an IP address and netmask |
L2Switch1(config-if)# no shutdown |
Enables the interface |
L2Switch1(config-if)# exit |
Returns to global configuration mode |
L2Switch1(config)# ip default-gateway 172.16.1.1 |
Assigns the default gateway address |
L2Switch1(config)# exit |
Returns to privileged EXEC mode |
L2Switch1# copy running-config startup-config |
Saves the configuration in NVRAM |